Neurotoxicity upon infusion of dimethylsulfoxide-cryopreserved peripheral blood stem cells in patients with and without pre-existing cerebral disease

Objective: Toxicity related to the infusion of dimethylsulfoxide (DMSO)-cryopreserved peripheral blood stem cells (DMSO-PBSC) mainly comprises cardiovascular events. Fatal neurotoxicity has been reported in a few cases. DMSO represents the putative causative agent of such rare toxicities and elaborate strategies to replace DMSO would benefit from the identification of predisposing factors for DMSO-related toxicities. Methods: Here, we report on DMSO-related neurotoxicity in a series of patients (n = 51) receiving DMSO-PBSC. The analyzed patient-series included eight patients with pre-existing cerebral disease, partially with a history of epileptic seizures. Results: Neurotoxicity was observed in only one patient who suffered from a generalized tonic seizure upon infusion of DMSO-PBSC and for which the clinical course is reported herein. No neurotoxicity was observed in the group of patients with pre-existing neurological disease. Furthermore, no neurotoxicity was observed in patients who received particularly large volumes of DMSO. In all patients, mild non-neurological side effects occurred but besides the reported seizure no other severe adverse events were observed upon PBSC-infusion. Conclusions: To our knowledge, this is the first report addressing the identification of predisposing factors for DMSO- related neurotoxicty. We conclude that infusion of DMSO-PBSC can be performed safely in patients with pre-existing cerebral disease despite the rare occurrence of severe neurotoxicity. Retrospective multicenter studies are warranted to identify patients who would benefit from elaborate methods of DMSO- replacement.